1. Field of the Invention PA1 2. Description of the Prior Art
The invention relates to a motor vehicle having a ventilation system including a movement transmission system in the ventilation system of the vehicle and, more specifically, to such a movement transmission system which employs a two wire configuration between a remote, manual adjustment device and a control device for controlling the ventilation system.
In the vehicle technology it is customary to transmit movement from an adjustment device arranged by the driver's seat in the vehicle to an element in a generally inaccessible location such as, for example, a control device for air distribution valves in the ventilation system of the vehicle. The transmission of movement can be accomplished both simply and inexpensively by means of a wire transmission in which a rigid wire is moved axially forwardly and backwardly in an enclosing sleeve in response to selective movement of the adjustment device. However, since the wire in these prior art designs can execute both pushing and pulling movements, the play which is experienced between the wire and the sleeve results in a form of hysteresis. When the distance between the adjustment device and the control device is short, the hysteresis does not result in any major problems. On the other hand, in the case of longer distances, the hysteresis experienced in longer wires of this type of wire transmission can be quite troublesome. Additionally, if a control device is intended to affect the movement of several air distribution valves, such a hysteresis could lead to excessively large variations in air distribution for the same setting of the adjustment device. In such cases where the hysteresis has tended to cause problems, it has not been uncommon to employ other forms of transmissions between the adjustment device and the control device such as, for example, electric or pneumatic transmissions.
However, it has been found that the components which are required for these other forms of transmissions are both complicated and expensive. As a result, they have been primarily used in more advanced ventilation systems such as, for example, entirely automatic ventilation systems.